For the first time, researchers have filmed the HIV virus spreading from one cell to the next, and they say the process by which it moves to an uninfected cell may provide a new target for future vaccines or treatments. The videosshow how an infected immune system T-cell hooks up with an uninfected cell, and passes a packet of viral particles through a structure called a virological synapse.

For decades it was believed that HIV was mostly spread around the body through freely circulating particles, which attach themselves to a cell, take over its replication machinery and make multiple copies of themselves…. Due to this, previous efforts to create an HIV vaccine have focused on priming the immune system to recognise and attack proteins of free-circulating virus [Telegraph]. While researchers discovered cell-to-cell transmission through the virological synapse earlier this decade, researchers say the videos highlight the extreme efficiency of this transmission process.

In the new study, published in Science, researchers note that HIV patients can develop antibodies that fight freely circulating HIV particles, which can at least slow the course of the infection, while not stopping it completely. However, these antibodies have no effect on cell-to-cell transmission, as the virus is hidden away inside T-cells. By going through cell-to-cell transmission, HIV evades one means the immune system uses to stop it [Pure Pedantry blog].

Study coauthor Benjamin Chen says the videos suggests that cell-to-cell transmission merits more research: “Most prior studies of HIV dissemination have focused on free- roaming viruses, but this study shows us how direct T-cell-to-T-cell contact could, in fact, be the predominant mode of dissemination within the body” [HealthDay News]. Adds study coautor Thomas Huser: “We should be developing vaccines that help the immune system recognise proteins involved in virological synapse formation and antiviral drugs that target the factors required for synapse formation” [Telegraph].